RFR: 8223145: [teststabilization] Replace wildcard address with loopback or local host in test - part 1

[mark sheppard]

<LE NOISE>
​
Hi Daniel,​
​
interesting set of changes -​
But could it be the case that, for some tests, you might change the operational semantics of a test, when​
this applying this change. For example, in the case of GetLocalAddress.​
The original is to use a wild card for the server, and a directed address for the ​
client connect. Thus the server is listening INADDR_ANY or the IPv6 equivalent, accepts​
a connection, then a check is made to see that socket created is bound to the same address​
as that specified in the clients connect request.​
​
If the server socket is  bound to a specific address then the socket created by the accept​
will (always)  have the same address as that of initial server socket (listener).​
​
As the tests are run with 3 different java.net property settings, it is worth asking if the tests behaves as expected​
for the case when neither java.net property is set.​
AFAIK, on windows it shows some ambiguity and difference to the default setting described in​
[1]. The default run returns IPV4 addresses, creates AF_INTET sockets and binds to IPv4 addresses.​
This is possibly at odds with the default property settings are described in the docs.​
​
java.net.preferIPv4Stack (default: false)​
If IPv6 is available on the operating system the underlying native socket will be, by default,​
an IPv6 socket which lets applications connect to, and accept connections from, both IPv4 and IPv6 hosts. ​
This implies that the first test run, i.e. default property settings, should be an AF_INET6 socket as in new ServerSocket​
should be bound to the IPv6 unspecified address.​
​
While​
java.net.preferIPv6Addresses (default: false)​
When dealing with a host which has both IPv4 and IPv6 addresses, ​
and if IPv6 is available on the operating system, the default ​
behavior is to prefer using IPv4 addresses over IPv6 ones.​
​
This implies that the InetAddress.getLocalHost() should in the default case​
return an IPv4 address.​
​
The client socket connect with IPv4 address to IPv6 wild card resulting in an IPv4 mapped​
binding in the socket created in the accept. This would mean the first run should fail.​
​
In any case a test using a server socket listening on a wildcard (INADDR_ANY) address has possibly​
slightly different semantics than a server socket listening on a specific host address.​
​
regards
Mark
​
</LE NOISE>​
​
[1] https://docs.oracle.com/javase/8/docs/api/java/net/doc-files/net-properties.html


________________________________
From: net-dev <net-dev-bounces at openjdk.java.net> on behalf of Daniel Fuchs <daniel.fuchs at oracle.com>
Sent: Tuesday 30 April 2019 11:16
To: OpenJDK Network Dev list
Subject: RFR: 8223145: [teststabilization] Replace wildcard address with loopback or local host in test - part 1

Hi,

Please find below a patch for:

8223145: [teststabilization] Replace wildcard address with loopback
          or local host in test - part 1
https://bugs.openjdk.java.net/browse/JDK-8223145

http://cr.openjdk.java.net/~dfuchs/webrev_8223145/webrev.00/

This is the first in a series of patches that will try to
address intermittent failures which are sometime observed
when tests use the wildcard address to bind their test servers.

These changes are IpV6-only friendly.

best regards,

-- daniel
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